Flexible Wheel/Rail Contact Model for Railway Vehicle Dynamics Without Pre-Calculation

2007 ◽  
Author(s):  
Mohammad Durali ◽  
S. Hassan Salehi ◽  
Mohammad Mehdi Jalili
Keyword(s):  
Vehicle Dynamics ◽  
Contact Forces ◽  
Contact Model ◽  
Railway Vehicle ◽  
Dynamic Problems ◽  
Vehicle Dynamic ◽  
Rail Vehicle ◽  
Rigid Contact ◽  
Contact Situation ◽  
Contact Mechanism

An advanced method using progressive concept of geometrical correspondence is applied to create a new wheel/rail contact model based on virtual penetration theory. The geometry and contact mechanism are solved simultaneously because of the independency in a defined correspondence. The model takes the penetrated profiles of wheel and rail and also associated creeps as inputs, and produces driving contact forces as output. The advantage of this model is that it doesn’t require pretabulation of rigid contact situation. The method allows calculating flexible, non-elliptical, multiple contact patches during integration of the model. Consequently the rails with substructures can vibrate separately from the vehicle in a flexible wheel/rail contact model. The simulation results indicate that this method can be used in various rail vehicle dynamic problems.

Numerical Procedure for Non-Hertzian Wheel-Rail Contact Model Integrated in Quasi-Steady Railway Vehicle Motion Solver

2020 ◽  
Author(s):  
Takayuki Tanaka ◽  
Hiroyuki Sugiyama
Keyword(s):  
Vehicle Dynamics ◽  
Numerical Procedure ◽  
Contact Model ◽  
Hertzian Contact ◽  
Railway Vehicle ◽  
Long Distance ◽  
Elliptical Contact ◽  
Vehicle Motion ◽  
Contact Shape ◽  
Dynamics Simulations

Abstract Although the Hertzian contact theory is widely utilized in railway vehicle simulations with new wheel and rail profiles, the Hertzian contact assumptions would lead to inaccurate contact prediction for severely worn wheel and rail profiles due to their geometric conformity, causing non-elliptical contact shapes as well as pressure distribution. For this reason, various non-Hertzian contact models have been studied for use in vehicle dynamics simulations. Among others, a method proposed by Piotrowski and Kik has gained acceptance in predicting non-elliptical wheel-rail contact for vehicle dynamics simulations. Despite the elegant formulation and its accuracy, detailed online geometric calculation for non-elliptical contact shape is required for all the contact patches at every iteration, along with iterative evaluation of the force-deflection relationship. It leads to computation burdens for use in long-distance vehicle simulations. Therefore, in this study, an off-line based numerical procedure for non-Hertzian contact model is developed and integrated in the quasi-steady railway vehicle motion solver.

Computer Simulation of the Response of a Railway Vehicle Carbody

2002 ◽  
Author(s):  
M. Senthil Kumar ◽  
P. M. Jawahar
Keyword(s):  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Lateral Stiffness ◽  
Lateral Vibration ◽  
Kutta Method ◽  
Nonlinear Mathematical Model ◽  
Rail Vehicle ◽  
Runge Kutta Method

In this paper, a nonlinear mathematical model has been constructed by deriving the equations of motion of a Rail Vehicle carbody using Newton’s law. The nonlinear formula is used to evaluate the wheel rail contact forces. The nonlinear profile of wheel and rail are taken into account. Also the lateral stiffness of the track is taken into consideration. The equations of motion are derived for (a) Carbody with conventional wheelset (b) Carbody with unconventional wheelset (independently rotating wheels). For lateral vibration, 17 degrees of freedom are considered. The degrees of freedom represent lateral and yaw movements of 4 wheelsets and lateral, yaw and roll movements of the bogie and carbody. These equations of motion are transformed into a form suitable for numerical differential equation by Runge Kutta method. In the interest of computing economy, certain approximations have been introduced for calculating the creep forces. Sample results are given for a model of a typical railway vehicle used by the Indian Railways. The lateral dynamic response of the railway vehicle carbody for both conventional and unconventional wheelset has been analysed.

Wheel/rail contact model for rail vehicle dynamics

2011 ◽  
Vol 339 (11) ◽  
pp. 700-707 ◽  
Author(s):  
Mohammad Mahdi Jalili ◽  
Hassan Salehi
Keyword(s):  
Vehicle Dynamics ◽  
Contact Model ◽  
Rail Vehicle ◽  
Rail Vehicle Dynamics

A Three-Dimensional Dynamic Model for Railway Vehicle–Track Interactions

2018 ◽  
Vol 13 (7) ◽  
Author(s):  
Xianmai Chen ◽  
Xiangyun Deng ◽  
Lei Xu
Keyword(s):  
Dynamic Models ◽  
Three Dimensional ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Time Integral ◽  
Proposed Model ◽  
Rigid Contact ◽  
Linearized Model ◽  
Pseudo Excitation ◽  
Force Equilibrium

In light of two wheel–rail contact relations, i.e., displacement compatibility and force equilibrium, a newly developed three-dimensional (3D) model for vehicle–track interactions is presented in this paper. This model is founded on the basis of an assumption: wheel–rail rigid contact. Unlike most of the dynamic models, where the interconnections between the vehicle and the track entirely depend on the wheel–rail contact forces, the subsystems of the vehicle and the tracks in the present study are effectively united as an entire system with interactive matrices of stiffness, damping and mass by the energy-variational principle and wheel–rail contact geometry. With wheel–rail nonlinear creepage/equivalent stiffness, this proposed model can derive dynamic results approaching to those of vehicle-track coupled dynamics. However, it is possible to apply a relatively large time integral step with numerical stability in computations. By simplifying into a linearized model, pseudo-excitation method (PEM) can be theoretically implemented to characterize the dominant vibration frequencies of vehicle-track systems due to random excitations. Finally, a trail method is designed to achieve the wheel climbing derailment process and a full derailment case where the bottom of the wheel flange has completely reached the rail top to form a complete derailment is presented.

Rigid Contact Model of Ultrasonic Motor Based on Finite Element Method

2011 ◽  
Vol 105-107 ◽  
pp. 495-499
Author(s):  
Chun Rong Jiang ◽  
Long Jin ◽  
Min Qiang Hu ◽  
Rui Xia Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Traveling Wave ◽  
Ultrasonic Motor ◽  
Contact Length ◽  
Contact Model ◽  
Frictional Material ◽  
Rigid Contact ◽  
Contact Mechanism ◽  
Element Method

Rigid contact model of rotor/stator in ring type traveling wave ultrasonic motor without frictional material based on finite element method is proposed in this paper. First, the vibration of the stator is analyzed. Next, the rigid contact model is simulated by finite element method. Subsequently, the contact mechanism of the rotor/stator as well as performance of the ultrasonic motor is studied, and the performance of motors with two different kinds of rotor is compared. It is indicated that contact length of the rotor/stator along circumferential direction decreases from the outer to the inner edge and the stall torque increases and no-load speed decreases with preload force increasing. The result is identified as being useful in designing and analyzing the ultrasonic motor.

Rail Vehicle Modelling and Simulation using Lagrangian Method

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Rakesh Chandmal Sharma ◽  
Sunil Kumar Sharma ◽  
Srihari Palli
Keyword(s):  
Vehicle Dynamics ◽  
Lagrangian Function ◽  
Railway Vehicle ◽  
Analytical Dynamics ◽  
Rail Vehicle ◽  
Vehicle System ◽  
Complete Set ◽  
Generalised Coordinates ◽  
Broad Understanding ◽  
Lagrange’S Method

Formulation of vehicle dynamics problem is dealt either with Newton’s method or Lagrange’s method. This paper provides a broad understanding of Lagrange’s method applied to railway vehicle system. The Lagrange’s method of analytical dynamics provides a complete set of equations through differentiations of a function called Lagrangian function which includes kinetic and potential energy with respect to independent generalised coordinates assigned to the system. This paper also discusses rigid body rotational dynamics along with the concept of generalised coordinates (constrained and un-constrained) and generalised forces in detail.

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